1. Field of the Invention
The present invention relates to detergent compositions, and, more particularly, to detergent compositions exhibiting an excellent detergency against protein soil. The present invention also relates to alkaline proteases which exhibit a high activity for hydrolyzing human horny keratin fiber and microorganisms which produce such proteases.
2. Description of the Background
Conventionally, various proteases have been incorporated into detergents for washing clothes and detergents for automated dish-washing machines in order to remove protein soil. Alkaline proteases exhibiting their activities in an alkaline region are used for such proteases.. Typical examples of such alkaline proteases are Alcalase, Savinase (a product of Novo Nordisk Co.), API-21 (Showa Denko Co., Ltd.), Maxacal (Gist Brocades Co.), and the like. Problems with many of these alkaline proteases have been their insufficient detergency against insoluble protein soils in such portions of clothes as collars, sleeves, and the like. Detergent compositions in which these alkaline proteases are incorporated do not exhibit sufficient detergency against protein soils.
Ya enzyme is reported (Japanese Patent Laid-open (kokai) No. 280278/1986) to be stable against surface active agents. This enzyme, however, is active on the high temperature range, and therefore generally is not suitable for use as a detergent to be used around room temperature.
Thus, there remains a need for detergent composition with a superior capability of removing protein soils, using an alkaline protease which is highly stable in surfactant solutions, active in a wide temperature range, and active for insoluble proteins.